1. Field of the Invention
The present invention relates to a battery storage mechanism in a battery-powered electric and/or electronic appliances such as an electronic calculator, an electronic memo, an electronic directory or the like.
2. Description of the Prior Art
A vast number of battery-powered electric and/or electronic appliances such as listed above is equipped with at least one erasable storage unit such as a random access memory for the storage of data inputted into the electric appliance. The problem hitherto encountered with this volatile storage unit is that all of the data inputted are erased the moment the battery in the electric appliance is run down or removed.
Therefore, it is a currently employed practice to employ a power storage capacitor parallel to a circuit line connecting between the electric power source and the storage unit so that, when the battery is removed, an electric charge built up in the power storage capacitor can be utilized for the power supply to the storage unit. This is effective to avoid any possible sudden erasure of the data stored in the storage unit. However, the removal of one battery is required to be followed by an immediate replacement with a fresh battery, or the electric charge in the power storage capacitor will run down with the stored data erased consequently.
In view of the foregoing, attempts have been made to use, in addition to a drive battery for driving major circuit component parts of the electric appliance, a back-up battery that is brought into operation to supply an electric power only to the storage unit and its associated component parts when the drive battery runs down or is to be removed. The use of the two batteries appears sophisticated, however, the conventional structure for accommodating such two batteries in the electric appliance is of a design that those batteries can be removed simultaneously, or of a design that, even though a means is provided for an alternate removal of the batteries, such means may occasionally work ineffective in the sense that the user of the electric appliance, if desiring, can remove them simultaneously or in succession.
For example, the Japanese Laid-open Utility Model Publication No. 59-88868, published June 15, 1984, discloses a battery storage structure having at least two juxtaposed pocket defined in a base plate for accommodating respective batteries. With the batteries seated within the respective pockets, each battery is retained in position within the associated pocket by means of a retainer strip extending over the respective battery with one end fitted into the base and the opposite end secured to the base by means of a set screw. To avoid a simultaneous removal of both batteries when and after both screws have been removed, this publication makes use of a tongue resiliently pivotable from a neutral position to any one of lateral positions defined on respective sides of the neutral position. This resiliently pivotable tongue has a width effective to avoid any possible simultaneous removal or detachment of the retainer strips even though the screws used to secure the respective ends of the retainer strips to the base have been removed, so long as the tongue is held in the neutral position. When the tongue is pivoted from the neutral position to one of the lateral positions by the application of an external force, one of the retainer strips remote from such one of the lateral positions for the tongue can be removed, allowing the battery, which has been retained in position within the associated pocket by means of such one of the retainer strips, to be removed.
According to the Japanese Laid-open Utility Model Publication No. 62-160459, published Oct. 12, 1987, and assigned to the same assignee of the present invention, discloses the at least two batteries retained within the respective pockets by means of a rotary retainer member having at least first and second portions spaced from each other with respect to the axis of rotation of the rotary retainer member. While the first portion of the rotary retainer member overlays one of the battery, the second portion is defined by two engagement pieces protruding radially outwardly of the circular path of movement of the retainer member for the engagement with a peripheral region of the other of the batteries. The rotary retainer members are shown and described as either a generally rectangular plate or a rotary disc having a radially inwardly recessed edge from which the engagement pieces extend radially outwardly.
The Japanese Laid-open Utility Model Publication No. 64-56142, published Apr. 7, 1989, discloses a battery storage structure substantially similar to the structure disclosed in the JP Laid-open UM Publication No. 62-160459 referred to above, but employs the rotary retainer member in the form of a sector-shaped plate movable from a neutral position to any one of lateral positions. This publication No. 64-56142 also discloses the use of resiliently retractable stoppers to keep the sector-shaped retainer plate in the neutral position, thereby to avoid any possible arbitrary movement of the retainer plate.
The Japanese Laid-open Utility Model Publication No. 62-160461, published Oct. 12, 1987, and assigned to the same assignee of the present invention, discloses a battery storage structure substantially similar to the structure disclosed in JP Laid-open UM Publication No. 62-1604459, but employs additionally a means for avoiding any possible arbitrary movement of the rectangular retainer member from one position to the opposite position once it has been moved from such opposite position to such one position with the associated battery removed. This means comprises a generally elongated members having a substantially intermediate portion integrated with the rectangular retainer member for movement together therewith and also having opposite ends engageable selectively into respective detent recesses that are communicated with the battery pockets. The movement of the retainer member is enabled only when a fresh battery is inserted into any one of the pockets which has been left vacant as a result of the removal of the used battery.
Again, the Japanese Laid-open Utility Model Publication No. 64-19256, published Jan. 31, 1989, and assigned to the same assignee of the present invention, discloses a generally rectangular slidable retainer plate supported for movement in a direction perpendicular to a line extending between the respective centers of the battery pockets. This slidable retainer plate has one end portion integrally formed with a lateral flange protruding outwardly from one side of the plate and the opposite end portion integrally formed with a similar lateral flange protruding outwardly from the opposite side of the plate. The flanges are offset relative to each other and protrude in the respective directions opposite to each other. When in the neutral position, the flanges of the retainer plate retains the respective batteries within the associated pocket, but when moved to one of the opposite positions on respective sides of the neutral position, one of the flanges clears from the associated battery while the other of the flanges remains in position to retain the other battery in the associated battery pocket. According to another embodiment disclosed therein, a means for avoiding any possible arbitrary movement of the retainer plate from the neutral position to any one of the lateral positions is also provided, which comprises a block piece, for each of the battery pocket, supported for movement in a direction perpendicular to the direction of movement of the retainer plate between block and release positions. When one of the block pieces is in the block position inhibiting the movement of the retainer plate from the neutral position towards one of the lateral positions, the other of the block piece is in the release position permitting the movement of the retainer plate from the neutral position towards the other of the lateral positions.
Although less pertinent to the present invention, the Japanese Laid-open Utility Model Publication No. 63-69360, published May 10, 1988, discloses a generally flat removable battery casing adapted to support thereon a flat battery and to be inserted into a battery chamber defined in the electric appliance. The battery casing looks like a desk drawer and has a spring strip integral with a wall of the casing and having first and second resilient portions opposite to each other. When and so long as the battery casing is accommodated within the battery chamber, the first and second resilient portions of the spring strip are engaged into detent recesses to avoid any possible detachment of the battery casing out from the battery chamber. Simultaneous disengagement of the first and second resilient portions from the associated detent recesses takes place when a pin or any thin member is inserted exteriorly to buckle the spring strip inwardly allowing the first and second resilient portions to be set back from the associated detent recesses.
Except for the disclosure made in the last mentioned publication, the system disclosed in any one of the foregoing publications is effective to avoid any possible erroneous removal of the plural batteries at one time which would eventually result in the erasure of the data stored in the volatile storage unit in the electric appliance. However, such system has been found having some inconveniences which will now be discussed.
In the first place, in order to make an access to any one of the batteries, a lid closing the battery chamber has to be removed with the use of a screw driver or the like. Also, it may often occur that the lid and/or a screw used to set the lid in position are likely to be lost when removed from the electric appliance in an attempt to carry out the battery replacement.
The removal of the lid used to close the battery chamber allow internal printed circuit boards and/or circuit component parts to be exposed bare to the outside and, therefore, depending on the type of electric appliance, some electronic component parts such as, for example, LSI elements, may be destroyed either physically or logically by the effect of an electrostatic charge built up on the user of the electric appliance.
Apart from the foregoing, it is generally recognized that the removal of the drive battery for the replacement with a fresh one may cause a drive unit (CPU or central processing unit) to run out of control to such an extent as to result in a logical destroy of the data stored in the storage unit such as a random access memory. In order to minimize this possibility, an attempt has been made to provide the electric appliance with a switching system operable to selectively establish a normal operating mode, in which an electric circuit between the drive unit and the storage unit is established, and a battery replacement mode in which the electric circuit therebetween is opened during the replacement of the battery. However, if the user of the electric appliance fails to manipulate the switching system to open the circuit between the drive and storage units prior to the actual replacement of the battery, this sophisticated switching system will not work and the drive unit will eventually run out of control.